Portable chain saw



FIG. 1 is a front, left perspective view of the portable chain saw according to the present invention;

FIG. 2 is a rear, right perspective view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a bottom plan view thereof; and,

FIG. 9 is a front, left perspective view thereof with a saw blade shown in broken lines.

The broken lines shown in FIGS. 8 and 9 represent unclaimed portions of the design and form no part thereof. 

The ornamental design for a portable chain saw, as shown and described. 